High resolution spotlight SAR self-focusing imaging method based on two-dimensional self-focusing

Abstract

The invention belongs to the radar technology field, discloses a high resolution spotlight SAR self-focusing imaging method based on two-dimensional self-focusing and mainly solves a problem that excellent focusing of a uniform imaging area can not be realized through a self-focusing algorithm in the prior art. The method comprises steps that an original echo signal of a target is received, after distance pulse pressure of the echo signal is carried out, crude envelope error and phase error compensation for the signal is carried out; distance direction FFT and azimuth solution linearity frequency modulation operation and two-dimensional interpolation operation are carried out; after distance direction IFFT of a result after two-dimensional interpolation is carried out, distance migration of a distance skipping unit is evaluated, and envelope error correction is accomplished; V non-superposed distance sub blocks are formed through uniform division along the distance direction, and a phase error of each sub block is evaluated; corresponding weights of distance units are respectively calculated, distance errors of the distance sub blocks are evaluated respectively, space-variant error evaluation is accomplished, azimuth direction IFFT of the data after correction is carried out, and thereby SAR images having the excellent focusing effect are acquired.

Description

technical field [0001] The invention relates to the field of radar signal processing, in particular to a high-resolution spotlight SAR self-focusing imaging method based on two-dimensional self-focusing, which can be used to compensate motion errors to obtain well-focused SAR images. Background technique [0002] With the development of synthetic aperture radar imaging technology, high-resolution spotlight SAR imaging has become a research hotspot in recent years. However, in the process of SAR data acquisition, the platform will be affected by factors such as atmospheric turbulence and its own vibration, and it is impossible to strictly move in a straight line at a uniform speed. Motion error will cause envelope error and phase error to appear in the SAR echo signal at the same time, which seriously affects the focus of the SAR signal, and motion compensation must be performed on the SAR echo data. [0003] Existing autofocus methods can be roughly divided into three categ...

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Problems solved by technology

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art, and propose a high-resolution spotlight SAR self-focusing imaging method based on two-dimensional self-focusing, so as to solve the problem that the existing self-focusing algorithm cannot focus well on the uniform imaging area

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